Attention-Deficit/Hyperactivity Disorder (ADHD) and depression/anxiety are often comorbid in children, and consequences of ADHD are more detrimental in lower socioeconomic levels. The aim of this study was to compare co-occurrence of ADHD and depression/anxiety with ADHD alone and depression/anxiety alone when the outcome measure is somatic complaints. Additionally, we examined whether low parental Socio-Economic Position (SEP) were related to occurrence of ADHD alone, depression/anxiety alone, and co-occurrence. The sample consisted of 12,900 parents who participated in a cross-sectional health survey that included Strengths and Difficulties Questionnaire (SDQ) and impact supplement. Socio-economic factors were dichotomized into low versus average/high parental socio-economic position (SEP), abdominal pain, neck pain and headache were categorized as somatic complaints. Parents described 58 % of the children with ADHD as comorbid with depression/anxiety. Children with ADHD only report somatic complaints when thedisorder is co-occurring with depression/anxiety. The prevalence of ADHD, depression/ anxiety, or a combination of the two disorders in children, is higher when parents have a low socio-economic position. Increased awareness of the heterotypic nature of ADHD is needed, especially when interpreting somatic complaints. There is a pattern of an inverse relationship between mental health and socio-economic position in children when measured by ADHD and depression/anxiety.